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1.
John F. Leatherland Brian J. Barnett C. Young Cho Stanley J. Slinger 《Environmental Biology of Fishes》1980,5(2):167-173
Synopsis Diets deficient in vitamin D effected a significant increase in plasma triiodothyronine (T3) concentration in raibow trout
(Salmo gairdneri); different levels of dietary calcium exerted no effect on plasma T3 levels. These effects of vitamin D deficiency on plasma
T3 levels appeared to be reversible, vitamin D supplementation after a period of vitamin D deficiency lowered T3 levels. Vitamin
D3, vitamin D2 and the metabolites 25(OH)-D3 and 1, 25(OH)2D3 were all effective in lowering plasma T3 levels; vitamin D3 appeared to be more effective than vitamin D2. There appeared to be a correlation between weight gain and plasma T3 concentration in the groups fed different types and
levels of vitamin D supplementation suggesting that the increased T3 levels may be a compensatory increase to the reduced
weight gain of the vitamin D deficient fish. Plasma T4 levels were not affected by dietary vitamin D deficiency. 相似文献
2.
In a study of 2,458 healthy non-anaemic subjects a positive correlation was found between haemoglobin levels and serum cholesterol and triglyceride levels. This may be due to simple changes in plasma volume, which may increase when the haemoglobin concentration decreases. Such an association between plasma lipid levels and haemoglobin values might be of importance in the aetiology of coronary heart disease, as a high haemoglobin value is known to be a “risk factor” in myocardial infarction. 相似文献
3.
The role of cytokines in the pathophysiology of amyotrophic lateral sclerosis (ALS) and its relation to clinical outcome has
not been clearly defined. We evaluated tumor necrosis factor-alpha (TNF-α), interferon-γ (IFN-γ) and nitric oxide (NO) levels
in the serum of 22 ALS patients and 20 controls. Serum TNF-α levels and IFN-γ levels were significantly (P < 0.001) elevated in ALS patients. We also observed NO levels to be significantly (P < 0.05) increased with respect to normal subjects. We further noticed positive correlation between the duration of ALS and
these proinflammatory molecule levels. Exitotoxicity and oxidative stress are known to play a crucial role in the neurodegeneration
observed in ALS. Since high levels of TNF-α are known to be cytotoxic, it could be that a complex interplay of these effectors
may be one of the factors underlying the progression of ALS. This study confirms the involvement of inflammation in ALS and
the need to develop surrogate markers to check the progression of this disease. 相似文献
4.
David J. Taylor Gene E. Robinson Barbara J. Logan Richard Laverty Alison R. Mercer 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1992,170(6):715-721
Summary Changes in biogenic amine levels associated with the morphological and behavioural development of the worker honeybee are examined.A significant increase in amine levels in the head of the honeybee is associated with transition from the larval to pupal stage. Adult emergence is also accompanied by a significant increase in 5-HT levels in the brain, but no significant change in brain dopamine (DA) levels. NADA (N-acetyldopamine) levels increase during larval and pupal development, but in contrast to both DA and 5-HT, drop significantly during the transition from pupa to adult.Levels of DA in the brain of nectar and pollen forager bees, presumed to be among the oldest adults sampled, were found to be significantly higher than in nurses, undertakers or food storers. These results suggest that an age-dependent change in amine levels occurs in the brain of the worker bee. In the optic lobes, levels of DA and 5-HT were found to be significantly higher in pollen forager bees than in all other behavioural groups. Significant differences in amine levels in the optic lobes of nectar foragers and pollen foragers indicate that some differences in amine levels occur independent of worker age. The functional significance of differences in brain amine levels and whether or not biogenic amines play a direct role in the control of honeybee behaviour has yet to be established.Abbreviations
DA
dopamine
-
5-HT
5-hydroxytryptamine or serotonin
-
NADA
N-acetyldopamine 相似文献
5.
J.-Ph. Moulinoux P. Le Pogamp V. Quémener M. Le Calvé V. Joyeux D. Chevet 《Life sciences》1981,29(9):955-962
Changes in red cell polyamine levels were studied in 25 chronic renal failure patients on maintenance hemodialysis. The data showed : 1) that putrescine levels are extremely low and could not be quantitated by the method used ; 2) spermidine and spermine were seen to be present mainly in the form of free polyamines, since the protein precipitate contained only traces of bound polyamines ; 3) pre-dialysis spermidine levels were consistently elevated, whereas spermine levels were abnormally high in only a small proportion of the patients ; 4) in 20% of cases a hemodialysis session brought about a fall of over 30% in polyamine levels, particularly in spermidine ; 5) in 5 patients in whom subsequent determinations were performed 2 or 4 months later, both the pre-dialysis levels and the effects of hemodialysis on these levels were unpredictable and could not be correlated with any clinical factors. Since a fall in urinary polyamine excretion is probably a cause of polyamine accumulation in red cells, it is likely that the changes in serum free polyamine levels in chronic renal failure patients undergoing hemodialysis could contribute to changes in red cell free polyamine levels. 相似文献
6.
Assay of calmodulin with Bordetella pertussis adenylate cyclase 总被引:3,自引:0,他引:3
Low levels of the calcium-dependent regulator protein, calmodulin, may be measured utilizing membranes prepared from Bordetella pertussis which contain and adenylate cyclase which is activated by this protein. The activation is dose dependent and tissue levels of calmodulin can be determined over a range from 2 pg to 100 ng with good reliability. We demonstrate how this bioassay may be employed to measure the levels of calmodulin in a variety of protein and cellular preparations. 相似文献
7.
Regiane Aparecida Canatto Bruno Éric Siqueira Albino 《International journal of phytoremediation》2021,23(1):102-110
Abstract Plants used in phytoremediation should accumulate and tolerate a specific pollutant. Here, we aimed at evaluating a possible arsenic (As) accumulation and mechanisms of tolerance against As-induced damage in Landoltia punctata to explore this species for phytoremediation. Plants were subjected to increasing As levels. As absorption was higher with increasing As levels. The activity of superoxide dismutase and glutathione reductase as well as anthocyanin levels increased with As levels. Catalase and peroxidase activities increased in plants subjected to As levels up to 1.0?mg L?1 and decreased at higher levels. Due to the antioxidant system, higher levels of reactive oxygen species were restrained in plants under low levels of As. However, the levels of superoxide anion, hydrogen peroxide, and lipid peroxidation increased in response to the impaired antioxidant system induced by the highest As levels. Biomass decreased in plants exposed to As and scanning electron microscopy revealed root structural damage in the root cap of plants under 3.0?mg L?1?As. This work highlights that L. punctata can be considered a hyperaccumulator species and has potential for As phytoremediation when levels are lower than 1.0?mg L?1—a concentration 100-fold higher than that recommended for drinking water. Novelty Statement: Landoltia punctata can be considered a hyperaccumulator species and has the potential for arsenic phytoremediation when levels are lower than 1.0?mg L?1. 相似文献
8.
Background
Fibroblast growth factor 19 (FGF19) and FGF21 are considered to be novel adipokines that improve glucose tolerance and insulin sensitivity. In the current study, we investigated serum FGF19 and FGF21 levels in patients with gestational diabetes mellitus (GDM) and explored their relationships with anthropometric and endocrine parameters.Method
Serum FGF19 and FGF21 levels were determined by enzyme-linked immunosorbent assay (ELISA) in patients with GDM (n = 30) and healthy pregnant controls (n = 60) matched for maternal and gestational age. Serum FGF19 and FGF21 levels were correlated with anthropometric, metabolic, and endocrine parameters.Results
Circulating levels of FGF19 were significantly reduced in patients with GDM relative to healthy pregnant subjects, whereas FGF21 levels were increased in GDM patients. Serum FGF19 levels independently and inversely correlated with insulin resistance (increased homeostasis model assessment of insulin resistance, HOMA-IR) and were positively related to serum adiponectin in both groups. In contrast, serum FGF21 levels independently and positively correlated with insulin resistance and serum triglycerides and were inversely related to serum adiponectin. In addition, in the combined population of both groups, those women with preconception polycystic ovary syndrome (PCOS) history had the lowest levels of FGF19, which were significantly lower than those in GDM patients without PCOS history and those in controls without PCOS history.Conclusions
Circulating FGF19 levels are reduced in GDM patients, in contrast with FGF21 levels. Both serum FGF19 and FGF21 levels are strongly related to insulin resistance and serum levels of adiponectin. Considering the different situation between FGF19 and FGF21, we suggest that reduced serum FGF19 levels could be involved in the pathophysiology of GDM, while increased serum FGF21 levels could be in a compensatory response to this disease. 相似文献9.
Nicotinate, nicotinamide, and the reactivity of leghemoglobin in soybean root nodules 总被引:2,自引:2,他引:0
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Nicotinate has been postulated to interfere with the binding of O2 to ferrous leghemoglobin in soybean (Glycine max) root nodules. For such a function, the levels of nicotinate in nodules must be sufficiently high to bind a significant amount of leghemoglobin. We have measured levels of nicotinate, nicotinamide, and leghemoglobin in soybean nodules from plants 34 to 73 days after planting in a glasshouse. On a per gram nodule fresh weight basis, levels between 10.4 and 21 nanomoles for nicotinate, 19.2 and 37.8 nanomoles for nicotinamide, and 170 to 280 nanomoles for leghemoglobin were measured. Even if all the nicotinate were bound to ferrous leghemoglobin, only 11% or less of the total leghemoglobin would be unavailable for binding O2. Using the measured levels of nicotinate and a pH of 6.8 in the cytosol of presenescent soybean nodules, we estimate that the proportion of ferrous leghemoglobin bound to nicotinate in such nodules would be less than 1%. These levels of nicotinate are too low to interfere with the reaction between ferrous leghemoglobin and O2 in soybean root nodules. 相似文献
10.
Florian J. Schweigert Wayne T. Stobo Hermann Zucker 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1990,159(6):649-654
Summary Vitamin E levels in serum, liver and blubber (subcutaneous adipose tissue) were determined for 66 male and female grey seals of varying age in the pupping colony on Sable Island in the Northwest Atlantic by high-performance liquid chromatography (HPLC). Fatty acid concentrations were determined for all blubber specimens. Adult males and pups had significantly higher levels of vitamin E and cholesterol in serum than females and juveniles. A close relationship between vitamin E and cholesterol in serum could be observed. Suckling pups had significantly higher levels of vitamin E in liver (191 mg·kg–1) than juveniles and adults (21–41 mg·kg–1). Levels of vitamin E in blubber showed an age-dependent increase, with the highest levels being found in adult males; overall, these levels were much lower than in man. Vitamin E levels in blubber and liver of lactating females were only half that of adult males. This might be due to an intensive transfer of vitamin E from mother to pup during lactation, a process which may also explain the much higher levels of vitamin E in serum and liver of nursing pups. The low levels of vitamin E in blubber of seals might be a result of its high percentage of unsaturated fatty acids (79%). Highest percentage was represented by 18:1, 16:1, 22:6 and 16:0. Pups had lower values of monounsaturated, and a higher percentage of saturated fatty acids compared to mothers. 相似文献
11.
Recent studies have posited that the pattern of glucocorticoid secretion within an individual represents a stable, fixed physiological trait. To test this hypothesis, we assessed the repeatability of baseline and stress-induced corticosterone (CORT) secretion across developmental stages and years in Florida scrub-jays. We sampled individuals from multiple cohorts repeatedly from the age of 11 days post-hatch up to 4 years of age. We found a significant degree of repeatability within individuals in stress-induced corticosterone levels, i.e., the amount of hormone secreted during a standardized stress protocol (corrected integrated corticosterone). However, baseline corticosterone levels were not statistically repeatable, although there was some indication that nestling levels predicted levels at 1 year of age. The results of this study indicate that stress-induced CORT levels are consistent within individual scrub-jays, and the degree to which a young jay mounts an acute stress response appears to be somewhat “set” by the age of nutritional independence. Thus stress-induced corticosterone secretion appears to be a stable, repeatable trait within individuals and as such may be subject to natural selection. 相似文献
12.
A A de Rotte T B van Wimersma Greidanus J M van Ree E A Andringa-Bakker D de Wied 《Life sciences》1981,29(8):825-832
β-Endorphin was able to enhance plasma α-MSH levels in rats after intracerebroventricular injection. This effect could be inhibited by naloxone or by removing tyrosine from position 61 of the peptide. Neither α- and γ-endorphin nor their des-tyrosine analogs appeared to be able to modify plasma α-MSH levels. The stimulating effect of β-endorphin on plasma α-MSH levels could be completely blocked by a simultaneous injection of apomorphine, in an amount in which apomorphine itself had no effect on α-MSH levels in plasma. A single injection of haloperidol increased plasma α-MSH levels in a dose related manner. A dose of haloperidol, which caused an apomorphine antagonizable increase in plasma α-MSH, did not modify β-endorphin elevated α-MSH levels. A high concentration of haloperidol was able to stimulate the basal release of α-MSH from isolated pituitaries , whereas β-endorphin appeared to be inactive in this respect.These observations indicate a central opiate receptor-mediated influence of β-endorphin on α-MSH release and the possible involvement of a dopaminergic system, mediating the β-endorphin effect. 相似文献
13.
Wolfgang Ostendorp 《Oecologia》1991,86(1):119-124
Summary The development of lakeside fringes of Phragmites reeds can be affected by high water levels, leading in extreme cases to die-back. A model is presented that allows estimation of the proportions of the damage. The model-formulated for 1 year and one Phragmites stalk—is based on the growth curve of the stalk, the altitude of the growth site, and the water level curve for the year. Applied to a reed stand over a series of years, the model is based upon the frequency distribution of the critical stalk length and the chance that the water level will be below a given value, each parameter being time dependent. Three case studies from Lake Constance-Untersee provide an example of the significance of episodic high water levels. Hence, aestival high water levels are expected to be one of the main factors controlling the lakeside frontline of the reedbelt. The model can be used in waterworks engineering, where reed plantations are to be established on the shores of lakes and reservoirs with strongly fluctuating water levels. 相似文献
14.
《Endocrine practice》2018,24(4):329-333
Objective: Existing transgender treatment guidelines suggest that for transmasculine treatment, there is a possible need for estrogen-lowering strategies adjunct to testosterone therapy. Further, guidelines advocate consideration of prophylactic female reproductive tissue surgeries for transgender men to avoid the possibility of estrogen-related health risks. Despite the paucity of objective data, some transgender men seek conversion inhibitors. We sought to determine estradiol levels in transgender men treated with testosterone therapy and the change in those levels with treatment, if any.Methods: Estradiol levels were extracted from the electronic medical records of 34 anonymized transgender men treated with testosterone therapy at the Endocrinology Clinic at Boston Medical Center. Data were sufficient to observe 6 years of follow-up.Results: With increased testosterone levels in trans-gender men, a significant decrease in estradiol levels was noted. There was a significant negative correlation between testosterone levels and body mass index, which may serve to explain part of the mechanism for the fall in estradiol levels. Even though the fall in estradiol levels was significant statistically, the actual levels remained within the normal male range, even with 6 years of follow-up.Conclusion: These data suggest that when exogenous testosterone is used to achieve normal serum male testosterone levels for transgender men, it is converted to normal male levels of estradiol, with some decline in those estradiol levels that might be attributable to a fall in fat mass. There appears to be no role for aromatase conversion inhibitors or other estrogen-reducing strategies in trans-gender men.Abbreviation: BMI = body mass index 相似文献
15.
Sexual differentiation of the brain has traditionally been thought to be driven by gonadal hormones, particularly testosterone (T). Recent studies in songbirds and other species have indicated that non-gonadal sex steroids may also be important. For example, dehydroepiandrosterone (DHEA) - a sex steroid precursor that can be synthesized in the adrenal glands and/or brain - can be converted into active sex steroids, such as 17β-estradiol (E2), within the brain. Here, we examine plasma DHEA and E2 levels in wild developing European starlings (Sturnus vulgaris), from hatch (P0) to fledging (P20). Blood samples were collected from either the brachial vein (n = 143) or the jugular vein (n = 129). In songbirds, jugular plasma is enriched with neurally-synthesized steroids and, therefore, jugular plasma is an indirect measure of the neural steroidal milieu. Interestingly, brachial DHEA levels were higher in males than females at P4. In contrast, jugular DHEA levels were higher in females than males at P0 and P10. Brachial E2 levels were higher in males than females at P6. Surprisingly, jugular E2 levels were not high and showed no sex differences. Also, we calculated the difference between brachial and jugular steroid levels. At several ages, jugular steroid levels were lower than brachial levels, particularly in males, suggesting greater neural metabolism of circulating DHEA and E2 in males than females. At a few ages, jugular steroid levels were higher than brachial levels, suggesting neural secretion of DHEA or E2 into the general circulation. Taken together, these data suggest that DHEA may play a role in brain sexual differentiation in songbirds. 相似文献
16.
Joseph Travis 《American journal of botany》1984,71(7):941-947
Observations of insects on Amianthium muscaetoxicum suggested that at least 16 species can serve as pollinators, although the chief pollinators appear to be beetles. Five species from three coleopteran families appear to be the most important pollinators. Experimental manipulations suggest that Amianthium is nearly self-incompatible and that fecundity and fruit set levels are at least partly pollinator limited. Outcrossed plants have higher fruit set and fertility levels than unmanipulated plants, and unmanipulated plants display higher levels than self-pollinated plants. Self-pollinated plants produce a few very small seeds, of which only a small percentage are viable. Fruit set levels in unmanipulated plants in one population were consistent over a 2-yr period. 相似文献
17.
Mohammed Al Bratty Yahya Hobani Julian A. T. Dow David G. Watson 《Metabolomics : Official journal of the Metabolomic Society》2011,7(4):542-548
Metabolomic profiling using hydrophilic interaction chromatography in combination with Fourier transform mass spectrometry
was used to study the effects of the xanthine oxidase inhibitor allopurinol on wild type Drosophila melanogaster. Allopurinol treatment phenocopied the rosy mutation causing an elevation in the levels of xanthine and hypoxanthine and
a fall in the levels of uric acid and allantoin. However, in addition there were some unexpected metabolic changes after treatment.
Ascorbic acid levels were undetectable, glutathione levels fell and glutathione disulphide levels rose, methionine S-oxide
levels rose and riboflavin levels fell. The origin of this oxidative stress was not immediately apparent; however, there was
a strong suggestion that it might be related to a fall in NADPH levels linked to a reduction in glucose-6-phosphate dehydrogenase
activity, resulting in reduced levels of some metabolites in the pentose phosphate pathway. In addition to producing oxidative
stress there were marked effects on tryptophan metabolism with most of the metabolites in the kynurenine pathway being lowered
by allopurinol treatment. The effects on the kynurenine pathway could be related to the established use of allopurinol in
treating schizophrenia. 相似文献
18.
Peter W. Barlow 《Acta biotheoretica》1992,40(4):321-328
The levels that compose biological hierarchies each have their own energetic, spatial and temporal structure. Indeed, it is the discontinuity in energy relationships between levels, as well as the similarity of sub-systems that support them, that permits levels to be defined. In this paper, the temporal structure of living hierarchies, in particular that pertaining to Human society, is examined. Consideration is given to the period defining the lifespan of entities at each level and to a periodic event considered fundamental to the maintenance of that level. The ratio between the duration of these two periods is found to be approximately 2.5 × 104. A similar relationship is found when lower, non-living levels of molecules and atoms are considered. This suggests that there is a constant factor of amplification between analogous periodic events at successive levels of the Human hierarchy. 相似文献
19.
Katina Aleksovska Emanuele Leoncini Stefano Bonassi Alfredo Cesario Stefania Boccia Alessandra Frustaci 《PloS one》2014,9(9)
S100B is a calcium-binding protein secreted in central nervous system from astrocytes and other glia cells. High blood S100B levels have been linked to brain damage and psychiatric disorders. S100B levels have been reported to be higher in schizophrenics than healthy controls. To quantify the relationship between S100B blood levels and schizophrenia a systematic literature review of case-control studies published on this topic within July 3rd 2014 was carried out using three bibliographic databases: Medline, Scopus and Web of Science. Studies reporting mean and standard deviation of S100B blood levels both in cases and controls were included in the meta-analysis. The meta-Mean Ratio (mMR) of S100B blood levels in cases compared to controls was used as a measure of effect along with its 95% Confidence Intervals (CI). 20 studies were included totaling for 994 cases and 785 controls. Schizophrenia patients showed 76% higher S100B blood levels than controls with mMR = 1.76 95% CI: 1.44–2.15. No difference could be found between drug-free patients with mMR = 1.84 95%CI: 1.24–2.74 and patients on antipsychotic medication with mMR = 1.75 95% CI: 1.41–2.16). Similarly, ethnicity and stage of disease didn''t affect results. Although S100B could be regarded as a possible biomarker of schizophrenia, limitations should be accounted when interpreting results, especially because of the high heterogeneity that remained >70%, even after carrying out subgroups analyses. These results point out that approaches based on traditional categorical diagnoses may be too restrictive and new approaches based on the characterization of new complex phenotypes should be considered. 相似文献
20.
Considerable evidence points to a role for B lymphocyte stimulator (BLyS) overproduction in murine and human systemic lupus
erythematosus (SLE). Nevertheless, the correlation between circulating levels of BLyS protein and disease activity in human
SLE is modest at best. This may be due to an inadequacy of the former to reflect endogenous BLyS overproduction faithfully,
in that steady-state protein levels are affected not just by production rates but also by rates of peripheral utilization
and excretion. Increased levels of BLyS mRNA may better reflect increased in vivo BLyS production, and therefore they may correlate better with biologic and clinical sequelae of BLyS overexpression than
do circulating levels of BLyS protein. Accordingly, we assessed peripheral blood leukocyte levels of BLyS mRNA isoforms (full-length
BLyS and ΔBLyS) and plasma BLyS protein levels in patients with SLE, and correlated these levels with laboratory and clinical
features. BLyS protein, full-length BLyS mRNA, and ΔBLyS mRNA levels were greater in SLE patients (n = 60) than in rheumatoid arthritis patients (n = 60) or normal control individuals (n = 30). Although full-length BLyS and ΔBLyS mRNA levels correlated significantly with BLyS protein levels in the SLE cohort,
BLyS mRNA levels were more closely associated with serum immunoglobulin levels and SLE Disease Activity Index scores than
were BLyS protein levels. Moreover, changes in SLE Disease Activity Index scores were more closely associated with changes
in BLyS mRNA levels than with changes in BLyS protein levels among the 37 SLE patients from whom repeat blood samples were
obtained. Thus, full-length BLyS and ΔBLyS mRNA levels are elevated in SLE and are more closely associated with disease activity
than are BLyS protein levels. BLyS mRNA levels may be a helpful biomarker in the clinical monitoring of SLE patients. 相似文献